Seriously the best advertising platform. Ever.
I see it constantly: companies hire someone to place post after post on their Facebook pages, but they don't get noticed. Reason? They are not being promoted. All that money spent to create those posts is simply money poured down the drain.
Facebook has evolved over the years, and recently made it necessary for businesses to spend money advertising those posts – which is fine, they need to make money somehow. The mistake most people make is to use that "Boost Post" button and not consider the audience they need to target.